Bug #4819

QGIS hangs when selecting a feature with the "Identify Features" tool

Added by Giovanni Manghi over 1 year ago. Updated 8 days ago.

Status:Reopened Start Date:01/16/2012
Priority:High Due date:
Assigned to:- % Done:

0%

Category:MapCanvas
Target version:Version 2.0.0
Platform: Patch supplied:Yes
Platform version: Affected version:1.8.0
Status info: Causes crash or corruption:Yes
Resolution:

Description

This happens with lines/polygons above a certain level of complexity (number of nodes). To test you can use the same vector that was used as test case in ticket #4523

http://www.faunalia.pt/downloads/test_slow_vector.zip

0001-4819_01.patch (1.7 kB) Thomas Arnold, 06/22/2012 01:44 am

sssi_problem.zip (1 MB) James Stott, 06/26/2012 01:06 am

slow_pan.zip (194.7 kB) James Stott, 06/26/2012 02:15 am

sssi_Identify.jpg - result after the use of identify feature tool (sssi_example) with the 0001-4819_01.patch (161.6 kB) Thomas Arnold, 06/26/2012 02:43 am

History

Updated by Giovanni Manghi about 1 year ago

  • Priority changed from 6 to High

Updated by Giovanni Manghi 11 months ago

  • Target version changed from Version 1.8.0 to Version 2.0.0
  • Affected version changed from master to 1.8.0

see also #5831

Updated by Thomas Arnold 11 months ago

hi,

if I load the example data "test_slow_vector.zip" and than selecting a feature qgis hangs after the method poly.subtracted( ring ) is calling in QgsHighlight::paintPolygon(...).
In the following patch I use QPainterPath to draw Polygons.

Updated by Giovanni Manghi 11 months ago

  • Patch supplied changed from No to Yes

Updated by James Stott 11 months ago

I am getting this problem too. The Identify Results window just goes blank and says 'Not Responding'. I have not found out how long it takes to return the results as I have have closed QGIS as it takes too long. It happens whether the data is in a shapefile or a postgis layer.

I have included an example of a polygon from the dataset that causes the problem. The polygon has over 80000 nodes. There are other polygons in this dataset that also do not work. The whole dataset is available from http://www.gis.naturalengland.org.uk/pubs/gis/GIS_Register.asp and is the Sites of Special Scientific Interest (England-wide) dataset.

Updated by James Stott 11 months ago

I have also noticed, that if I can get a polygon to identify without hanging, then if I keep it highlighted from the identify tool (in red) and pan, the panning is very slow. Once the polygon that is selected by the identify tool is off screen, panning speeds up again.

To reproduce, use identify tool to select polygon, now pan the map.

Example polygon attached.

Updated by Thomas Arnold 11 months ago

Hi,

did you use the patch? With the patch the selecting of the a feature with the identify feature tool in the sssi_problem example works ok for me (see sssi_Identify.jpg). I'm working with qgis 1.8 on windows 7 with osgeo installation.

Updated by Giovanni Manghi 11 months ago

Thomas Arnold wrote:

Hi,

did you use the patch? With the patch the selecting of the a feature with the identify feature tool in the sssi_problem example works ok for me (see sssi_Identify.jpg). I'm working with qgis 1.8 on windows 7 with osgeo installation.

I didn't had the time to try the patch yet, but please if it works (and I'm sure it does) then raise the issue in the dev mailing list. I have one it a couple of days ago but had no answers. This is a huge usability issue, and it is not tagged as blocker just because is not a regression.

Updated by James Stott 11 months ago

No. How do I apply the patch to test it? using osgeo4w.

Updated by Thomas Arnold 11 months ago

Giovanni Manghi wrote:

Thomas Arnold wrote:

Hi,

did you use the patch? With the patch the selecting of the a feature with the identify feature tool in the sssi_problem example works ok for me (see sssi_Identify.jpg). I'm working with qgis 1.8 on windows 7 with osgeo installation.

I didn't had the time to try the patch yet, but please if it works (and I'm sure it does) then raise the issue in the dev mailing list. I have one it a couple of days ago but had no answers. This is a huge usability issue, and it is not tagged as blocker just because is not a regression.

Thank you for trusting in the patch ;-). I had read the dev mailing list and it seem to me that the dev has a lot to do with the qgis 1.8 release. I am very confident that in a few days a developer will look at this ticket.

James Stott wrote:

No. How do I apply the patch to test it? using osgeo4w.

It is a source code patch. There are two ways: ether (easy way) wait some days until the patch will accepted and applied (than install qgis-dev) or (difficult way) download the source code, apply the patch with git apply ????.patch and building QGIS from source as descriped in http://www.qgis.org/api/INSTALL.html#toc14.

Updated by Magnus Homann 8 months ago

  • Status changed from New to Closed

This seems to be applied in master.

Updated by Giovanni Manghi 8 months ago

Magnus Homann wrote:

This seems to be applied in master.

it seems so, now it is usable and does not freeze even if it is not lightning fast, but anyway is ok.

Updated by Andre Joost 8 days ago

  • Status changed from Closed to Reopened

The problem still exists, see http://hub.qgis.org/issues/7834 and http://gis.stackexchange.com/questions/60678/qgis-bad-allocation-exception-on-identify
Zoomed to extent, identify works, but with high zoom levels (1:1000 or less) a permanent "Bad Allocation" error occurs.

Current Master on Windows XP exits without any message.

On Ubuntu, Lisboa and Master work without problem.

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